Aesthetic self-ligating orthodontic bracket

ABSTRACT

A self-ligating orthodontic bracket for captivating an archwire with a tooth. The bracket includes a bracket body mountable to a tooth and a self-ligating mechanism having an archwire slot and a ligating slide. The ligating slide is movable between an open position in which an archwire is insertable into the archwire slot and a closed position in which the archwire is retained in the archwire slot. The bracket body may be formed from a non-metallic material, such as a polymer, a filled polymer composite, or a ceramic, and the self-ligating mechanism may be formed from a metal. The bracket may include a resilient engagement member with a detent positioned to engage an aperture extending through the ligating slide when the ligating slide is in the closed position.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/404,345 filed on Aug. 19, 2002, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The invention relates generally to orthodontic brackets and, moreparticularly, to self-ligating orthodontic brackets.

BACKGROUND OF THE INVENTION

[0003] Orthodontic brackets represent a principle component of allcorrective orthodontic treatments devoted to improving a patient'socclusion. Conventional orthodontic treatments affix brackets to thepatient's teeth and an archwire is threaded through a slot of eachbracket. The archwire applies corrective forces that coerce the teeth tomove to orthodontically correct positions. Traditional ligatures, suchas small elastomeric O-rings or fine metal wires, are employed to retainthe archwire within each bracket slot. Due to difficulties encounteredin applying an individual ligature to each bracket, self-ligatingorthodontic brackets have been developed that eliminate the need forligatures by relying on a movable latch or slide for captivating thearchwire with the bracket slot.

[0004] Conventional orthodontic brackets are ordinarily formed fromstainless steel, which is strong, nonabsorbent, weldable, and relativelyeasy to form and machine. Patients undergoing orthodontic treatmentusing metal orthodontic brackets, however, may be embarrassed by thevisibility of conventional metal orthodontic brackets, which are notcosmetically pleasing. To improve the cosmetic appearance, certainconventional orthodontic brackets incorporate a bracket body of atransparent or translucent non-metallic material, such as a polymerresin or a ceramic, that assumes or mimics the color or shade of theunderlying tooth. Such orthodontic brackets may rely upon a metallicinsert lining the archwire slot for strengthening and reinforcing thebracket body in the vicinity of the archwire slot. As a result, theappearance of metal in the patient's mouth is less noticeable inordinary view and, therefore, brackets characterized by a non-metallicbracket body are more aesthetically pleasing. However, conventionalorthodontic brackets with non-metallic bracket bodies have yet toimplement self-ligation as self-ligating brackets necessitate the use ofmetallic materials because of the strength, ductility and toughness ofmetals as compared to other non-metallic materials.

[0005] Conventional self-ligating orthodontic brackets suffer from otherdeficiencies. For example, certain self-ligating brackets apply a springforce to hold a ligating slide in a closed position to captivate anarchwire. When the ligating slide is moved between from the closedposition to an open position, the spring force continues to act againstthe ligating slide and opposes the movement.

[0006] Thus, there would be a need for a self-ligating orthodonticbracket that overcomes these deficiencies of conventional self-ligatingorthodontic brackets.

SUMMARY OF THE INVENTION

[0007] The invention overcomes the foregoing and other shortcomings anddrawbacks of conventional self-ligating orthodontic brackets, asdescribed above. According to the principles of the invention, anorthodontic bracket includes a bracket body configured to be mounted toa tooth and a metallic self-ligating assembly carried by the bracketbody including an archwire slot and a ligating member movable between anopen position in which an archwire is insertable into the archwire slotand a closed position in which the archwire is retained in the archwireslot. The bracket body is formed from a non-metallic material, such as apolymer, a filled polymer composite, or a ceramic. In accordance withthe principles of the invention, the metallic insert includes aself-ligating member, which differs from conventional orthodonticbrackets having non-metallic bracket bodies in which the metallic insertmerely operates as a liner for the archwire slot.

[0008] In accordance with another embodiment of the invention, aself-ligating orthodontic bracket includes a bracket body configured tobe mounted to a tooth and a ligating slide carried by the bracket bodyfor movement between an open position in which an archwire is insertableinto an archwire slot of the bracket body and a closed position in whichthe ligating slide retains the archwire in the archwire slot. Theself-ligating orthodontic bracket further includes a resilientengagement member positioned to engage a recess in the ligating slidewhen the ligating slide is in the closed position. The engagementbetween the resilient engagement member and recess effectivelyconstrains movement of the ligating slide relative to the bracket body.

[0009] In accordance with yet another embodiment of the invention, aself-ligating orthodontic bracket includes a ligating slide and abracket body configured to be mounted to a tooth. The bracket body hasan archwire slot and a pair of opposed guides supporting the ligatingslide. The guides operate to guide the ligating slide for movementbetween an open position in which an archwire is insertable into thearchwire slot and a closed position in which the archwire is retained inthe archwire slot. At least one of the guides includes a recess capableof being engaged by a resilient engagement member when the ligatingslide is in the closed position for constraining movement of theligating slide relative to the bracket body.

[0010] In accordance with yet another embodiment of the invention, anapparatus for coupling an archwire with a tooth includes a bracket bodyconfigured to be mounted to a tooth and a ligating slide carried by thebracket body for movement between an open position in which an archwireis insertable into an archwire slot in the bracket body and a closedposition in which the ligating slide retains the archwire in thearchwire slot. The ligating slide includes a rear surface facing thetooth, a front surface opposite to the rear surface, and an apertureextending from the front surface to the rear surface. A resilientengagement member is capable of engaging the ligating slide in theclosed position for constraining movement of the ligating slide relativeto the bracket body. The apparatus further includes a tool including ashoulder and a tip projecting from the shoulder by a distance sufficientto deflect the resilient engagement member so that the ligating slidemay be moved from the closed position to the open position when theshoulder contacts a portion of the ligating slide surrounding theaperture.

[0011] In accordance with yet another embodiment of the invention, aself-ligating orthodontic bracket includes a bracket body configured tobe mounted to a tooth and a ligating slide carried by the bracket bodyfor movement between an open position in which an archwire is insertableinto an archwire slot of the bracket body and a closed position in whichthe ligating slide retains the archwire in the archwire slot. Theligating slide includes a rear surface facing the tooth, a front surfaceopposite to the rear surface, and a tool-engaging element accessiblefrom the front surface. The front surface of the ligating slide has achannel effective for guiding the movement of a tool contacting thefront surface and moving toward the tool engaging element.

[0012] In accordance with yet another embodiment of the invention, aself-ligating orthodontic bracket includes a bracket body configured tobe mounted to a tooth and a ligating slide carried by the bracket bodyfor movement between an open position in which an archwire is insertableinto an archwire slot in the bracket body and a closed position in whichthe ligating slide retains the archwire in the archwire slot. Theorthodontic bracket further includes a deflecting element on the bracketbody that deflects objects in a patient's oral cavity away from aperipheral edge of the ligating slide when the ligating slide is in theclosed position and the bracket body is mounted to the tooth.

[0013] In accordance with yet another embodiment of the invention, aself-ligating orthodontic bracket includes a bracket body configured tobe mounted to a tooth and a ligating slide carried by the bracket bodyfor movement between an open position in which an archwire is insertableinto an archwire slot in the bracket body and a closed position in whichthe ligating slide retains the archwire in the archwire slot. Theligating slide includes at least one stop element that abuts a stopelement on the bracket body when the ligating slide is in the openposition.

[0014] The above and other objects and advantages of the invention shallbe made apparent from the accompanying drawings and the descriptionthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and, together with a general description of the inventiongiven above, and the detailed description of the embodiments givenbelow, serve to explain the principles of the invention.

[0016]FIG. 1 is a perspective view of a self-ligating orthodonticbracket according to the principles of the invention in which theligating slide is removed from the assembly for clarity.

[0017]FIG. 2 is a perspective view of the self-ligating orthodonticbracket of FIG. 1 in which the movable slide is in a latched conditionfor capturing an archwire, not visible in FIG. 2, in the archwire slot.

[0018]FIG. 3 is a perspective view similar to FIG. 2 in which themovable slide is in an unlatched condition affording access to thearchwire slot.

[0019]FIG. 4 is a cross-sectional view of the self-ligating orthodonticbracket of FIG. 2 shown with an archwire captured in the archwire slot.

[0020]FIG. 5 is a cross-sectional view of the self-ligating bracket ofFIG. 3.

[0021]FIG. 6 is a view of an alternative embodiment of an orthodonticbracket according to the principles of the invention.

[0022]FIG. 7 is a view of another alternative embodiment of aself-ligating orthodontic bracket in accordance with the principles ofthe invention.

[0023]FIG. 8 is a view of another alternative embodiment of aself-ligating orthodontic bracket in accordance with the principles ofthe invention.

[0024]FIG. 9 is a cross-sectional view taken generally along line 9-9 inFIG. 8 in which the locking wire is deflected occlusal/gingivally.

[0025]FIG. 10 is an enlarged view of a portion of FIG. 8 in which thelocking wire is deflected inwardly toward the tooth.

[0026]FIG. 11 is an exploded perspective view of another alternativeembodiment of a self-ligating orthodontic bracket in accordance with theprinciples of the invention.

[0027]FIG. 12 is a perspective view of the self-ligating orthodonticbracket of FIG. 11 in which the movable slide is in an unlatchedcondition.

[0028]FIG. 13 is a perspective view of the self-ligating orthodonticbracket of FIG. 11 in which the movable slide is in a latched condition.

[0029]FIG. 14 is a cross-sectional view of the self-ligating orthodonticbracket of FIG. 13.

[0030]FIG. 15 is a perspective view of a portion of a tool suitable formoving the movable slide between latched and unlatched conditions.

DETAILED DESCRIPTION

[0031] Although the invention will be described next in connection withcertain embodiments, the invention is not limited to practice in any onespecific type of self-ligating orthodontic bracket. The description ofthe embodiments of the invention is intended to cover all alternatives,modifications, and equivalent arrangements as may be included within thespirit and scope of the invention as defined by the appended claims. Inparticular, those skilled in the art will recognize that the componentsof the embodiments of the invention described herein could be arrangedin multiple different ways.

[0032] With reference to FIGS. 1-5, an orthodontic bracket, generallyindicated by reference numeral 10, includes a bracket body 12, aself-ligation insert 14 partially embedded or insert molded within thebracket body 12, a movable ligating slide 16 slidably coupled with theself-ligation insert 14, and a resilient engagement member or spring arm18 that regulates the ability of the ligating slide 16 to move relativeto the self-ligation insert 14. The spring arm 18 also locks the slide16 in an open or unlatched position (FIG. 3) and a closed or latchedposition (FIG. 2). The bracket body 12 and self-ligation insert 14collectively form an orthodontic bracket structure for use in correctiveorthodontic treatments.

[0033] The bracket body 12 has a bonding base 20, an occlusal side 22when mounted to a tooth carried by the patient's lower jaw, a gingivalside 24, a plurality of, for example, two orthodontic tie wings 26, 28formed on the gingival side of body 12, a pair of side flanges 30, 32,two spaced archwire slot portions 34, 36 defined occlusal/gingivallybetween each of the tie wings 26, 28 and a corresponding one of the sideflanges 30, 32, and a recessed groove 33 extending in a mesial/distaldirection between the side flanges 30, 32. The recessed groove 33 isaligned with the archwire slot portions 34, 36, which likewise extend ina mesial/distal direction. The tie wings 26, 28 are spaced in amesial/distal direction and provide orthodontic attachment points to,for example, apply torsional forces to the tooth. The bonding base 20 ofthe bracket body 12 is configured to be secured to a tooth in anyconventional manner, for example, by an appropriate orthodontic cementor adhesive.

[0034] With continued reference to FIGS. 1-5, the self-ligation insert14 includes a base wall 41 and a pair of opposed slot walls 37, 39projecting labially from the base wall 41 that collectively defining anarchwire slot 38 extending in a mesial/distal direction. Theself-ligation insert 14 further includes a pair of guides 40, 42positioned on respective mesial and distal sides above the archwire slot38 and a planar member 45 extending from slot wall 39 and carrying theguides 40, 42. The guides 40, 42 are generally L-shaped and projectoutwardly from the planar member 45 in a labial direction. The slotwalls 37, 39 and base wall 41 are substantially encapsulated or embeddedwithin the material of the bracket body 12. The guides 40, 42 arepositioned on the side of the archwire slot 38 opposite to the slot wall37. The archwire slot 38 and the archwire slot portions 30, 32 of thebracket body 12 are collectively designed to receive an orthodonticarchwire 43 (FIG. 4) in the same manner as typical prior art orthodonticbrackets.

[0035] Opposite mesial/distal peripheral edges of the ligating slide 16are movably and slidably engaged between the planar member 45 and thecorresponding one of the mesial and distal guides 40, 42. The ligatingslide 16 is movable occlusal/gingivally relative to the bracket body 12between an open or unlatched position in which the arch wire 43 isinsertable into the archwire slot 38 and a closed or latched position inwhich the arch wire 43 is captured or enclosed in the archwire slot 38.Slot wall 37 is recessed below the surrounding surface of the bracketbody 12 so that, when the ligating slide 16 is in the closed position, aperipheral portion of the slide 16 contacts bracket body 12 on the sideof the self-ligating insert 14 opposite to the attachment of the guides40, 42.

[0036] The spring arm 18 regulates the movement of the ligating slide 16relative to the bracket body 12 and self-ligating insert 14 and alsoprevents accidental or unintentional detachment of the ligating slide 12from the self-ligation insert 14 during use regardless of whether theligating slide 12 is left in an open or closed position. The spring arm18 operates to couple the ligating slide 16 with the bracket body 12 andlocates the ligating slide 12 relative to the bracket body 12 in theopen and closed positions.

[0037] The spring arm 18 is generally L-shaped and is alignedperpendicularly relative to the archwire slot 38. One labially-extendingend of the spring arm 18 is secured with the self-ligating insert 14 sothat the spring arm 18 extends between the guides 40, 42 for mechanicalcoupling with a blind opening 44 formed in the planar member 45. Thespring arm 18 may be secured to the self-ligating insert 14 or maymerely be confined or trapped between the ligating slide 16 and theself-ligating insert 14. An opposite end of the spring arm 18 isprovided with a labially-extending detent or projection 46, which maybe, for example, rectangular or cylindrical in cross-section.

[0038] With continued reference to FIGS. 1-5, the ligating slide 16 is agenerally planar structure having an elongate slot or recess 48 (FIG. 4)opening toward the tooth surface and configured for receiving the springarm 18, a flange 50 extending outwardly in a mesial/distal directionfrom a side edge, a flange 52 extending outwardly in a mesial/distaldirection from an opposite side edge, and a flange 53 extendinglabially/lingually. The flanges 50, 52 and 53 are arranged about theouter margin of the ligating slide 16. Flange 50 is engaged with guide40 of the self-ligating insert 14 for sliding movement and flange 52 isslidingly engaged with the distal guide 42. Flange 53 of the ligatingslide 38 abuts two outwardly-projecting portions of slot wall 37 thatare spaced in the mesial/distal direction

[0039] The elongated recess 48 has an open end 54 opening occlusally orgingivally and a closed wall 56 opposite the open end 54. Extendingligually/labially through the ligating slide 16 near the open end 54 isan aperture or opening 58, which corresponds in cross-sectional profilewith the cross-sectional profile of the projection 46. The spring arm 18is capable of resiliently cantilevering relative to the ligating slide16 for selectively engaging the projection 46 with the opening 58 so asto lock the ligating slide 16 in its closed position. To that end, thespring arm 18 is resiliently biased in a direction that forces theprojection 46 outwardly in a gingival away from the tooth and toward theligating slide 16.

[0040] The spring arm 18 operates to retain ligating slide 16 in eitherthe open or closed position and controls the release of the ligatingslide 16 while the bracket 10 is worn on a tooth. To that end, thespring arm 18 provides positive stops for the ligating slide 16 in theopen and closed positions without overcoming a biasing force during thetransitions between the open and closed positions. In other words, thespring arm 18 locks the ligating slide 16 in the open and closedpositions independent of the biasing force of the spring arm 18. Thespring arm 18 merely operates for establishing the open position bycoercing the projection 46 to engage opening 58 and the closed positionby abutting against an inwardly-facing surface of closed wall 56.

[0041] In certain embodiments of the invention, the bracket body 12 maybe made of any aesthetically-pleasing substantially transparent,translucent or tooth-colored material, such as a ceramic or a polymerresin. Suitable polymer resins include, but are not limited to,polycarbonate, acrylic-based thermoplastic resins, acrylic thermosetresins, and other structural plastics. The polymer resin may bereinforced or filled with a filler, such as glass spheres, orreinforcing fibers, such as glass fibers, to provide a composite thatimproves the rigidity and strength of the bracket body 12. Suitableceramics include polycrystalline aluminum oxide, sapphire, toughenedzirconia and yttrium-stabilized zirconia.

[0042] In these embodiments, the self-ligation insert 14 is made by anysuitable forming technique, such as metal injection molding (MIM), froma biocompatible metal, such as a stainless steel and, more specifically,a 17-4 stainless steel. The spring arm 18 is made from any suitablematerial, including stainless steels, titanium alloys and Ni/Ti typesuperelastic materials. One particularly suitable material for springarm 18 is 17-7 PH stainless steel. The ligating slide 16 may be formedby any suitable process, such as MIM, from any biocompatible material,including metals such as stainless steel, or as a metal core membersurrounded at least partially by a thin shell of a ceramic, such as analuminum oxide, titanium nitride or titanium oxide, colored to have theappearance of a natural tooth enamel and which may be shaded tocorrespond to the shading of a specific patient's enamel. The bracketbody 12, the self-ligation insert 14, and the ligating slide 16 areassembled by any conventional molding technique, such as injectionmolding.

[0043] In other specific embodiments of the invention, the orthodonticbracket 10 may be formed entirely from metal without departing from thespirit and scope of the invention. In still other specific embodimentsof the invention, the metallic self-ligating insert 14 may assumedifferent constructions, such as a metallic hinged closure, and is notlimited to a sliding ligating mechanism.

[0044] In use and with reference to FIGS. 1-5, the ligating slide 16 inthe closed position blocks the entrance to the archwire slot 38 tocapture the archwire 43 therein and the engagement between projection 26and opening 58 provides a latched condition. The ligating slide 16unlocked using an end of a tool (FIG. 15) designed to press theprojection 46 inwardly (i.e., lingually) toward the tooth with a forcesufficient to overcome the bias applied by spring arm 18 and disengagethe projection 46 from the opening 58 in the ligating slide 16 toprovide an unlatched condition. When the projection 46 is moved by thetool inwardly (i.e., lingually) by a distance adequate to substantiallyclear the plane of the backside of the ligating slide 16, the ligatingslide 16 is freely movable using a force applied by the toolocclusal/gingivally toward the open position in a slidably manner guidedby guides 40, 42. The motion of the ligating slide 16 is positivelystopped in the open position by contact between the bend 62 of thespring arm 18 and the closed wall 56 of the elongated recess 48.

[0045] To place the ligating slide 16 in the closed position, slide 16is moved occlusal/gingivally until the projection 46 springs outwardlyunder the bias applied by spring arm 18 and is received in the opening58. The ligating slide 16 is then securely locked in the closedposition. The engagement of the projection 46 into the opening 58 maycreate a tactile effect which is perceptible to a clinician and/or emitsan audible sound, such as a click, that is likewise perceptible by aclinician. The ligating slide 16 may be moved occlusal/gingivally usingthe tool described above or simply pushed occlusal/gingivally using adifferent type of tool, or the clinician's fingertip, by contact withthe edge of flange 53 because the ligating slide 16 is freely movableocclusal/gingivally without overcoming the spring force applied by thespring arm 18.

[0046] The resilient bias applied by the spring arm 18 does not act onthe ligating slide 16 other than to engage the projection 46 with theopening 58 and to locate the bend 62 relative to the closed end of theelongate recess 48. It follows that the spring arm 18 is not operativelycoupled with the ligating slide 16 for providing a force that moves theligating slide 16 relative to the bracket body 12. Moreover, theligating slide 16 does not have to overcome the resilient force of thespring arm 18 during movement.

[0047] With reference to FIG. 6 and in an alterative embodiment, the tiewings 26, 28 may be redimensioned to project outwardly (i.e., labially)beyond or above the edge of slot wall 37. As a result, the leadingexterior edge of the closed wall 56 abuts against the side of the tiewings 26, 28 when the ligating slide 16 is in the closed position.

[0048] With reference to FIG. 7 in which like reference numerals referto like features in FIGS. 1-5, an orthodontic bracket 10′ in accordancewith an alternative embodiment of the invention includes a bracket body12′, a self-ligating insert 14′ embedded or insert molded within thebracket body 12′, a movable ligating slide 16′ slidably coupled with theself-ligation insert 14′, and a resilient engagement member consistingof a pin 70 and a resilient member 72 that biases the pin 70 toward theligating slide 16′ for regulating the movement of the ligating slide 16′relative to the self-ligation insert 14′. The components of orthodonticbracket 10′ are substantially similar to those of orthodontic bracket10, other than noted below. The orthodontic bracket 10′ is illustratedwith the ligating slide 16′ moved to a closed position in FIG. 12.

[0049] The bracket body 12′ incorporates a cylindrical bore 74, whichmay be a blind bore, into which the resilient member 72, illustrated asa compression spring, is received. The resilient member 72 is capturedin a compressed state between a collar 76 of the pin 70 and the closedend of blind bore 74. The compression of the resilient member 72 createsa labially-directed bias. Extending outwardly from the collar 76 is acylindrical detent or projection 80. When the ligating slide 16′ is inthe closed position, a gingival side of the collar 76 contacts theunderside of the slide 16′ and the projection 80 is received in anaperture or opening 82 provided in the ligating slide 16′. Theengagement between the projection 80 and opening 82 operates to retainligating slide 16′ in either the open or closed position and controlsthe release of the ligating slide 16′ while the bracket 10′ is worn on atooth.

[0050] To provide an open position, the projection 80 is pressedinwardly toward the tooth using a tool (not shown) with a forcesufficient to overcome the bias applied by resilient member 72 fordisengaging the projection 80 from the opening 82. When the projection80 is moved inwardly by a distance adequate to substantially clear theplane of the backside of the ligating slide 16′, the ligating slide 16′may be moved slidably toward the open position. In the open position,the projection 80 contacts an end wall 84 of the recess to provide apositive stop such that the ligating slide 16′ is captivated to thebracket body 12′. To move the ligating slide 16′ from the open positionto the closed position is accomplished by moving the slide 16′occlusal/gingivally until the projection 80 springs outwardly under thebias applied by resilient member 72 and is received in the opening 82.The ligating slide 16′ is then securely locked in the closed position.The resilient member 72 is for the purpose of engaging and disengagingthe member 72 into and out of the opening 82.

[0051] With reference to FIGS. 8-10 in which like reference numeralsrefer to like features in FIGS. 1-5, an orthodontic bracket 10″ inaccordance with an alternative embodiment of the invention includes aself-ligation insert 14″ embedded or insert molded within the bracketbody (not shown), a movable ligating slide 16″ slidably coupled with theself-ligation insert 14″, and a resilient engagement member consistingof a locking wire 90 fixed at one end 92 to the ligating slide 16″. Thelocking wire 90 extends in a mesial/distal direction though a passageway93 formed in flange 152 of the ligating slide 16″ and an opposite end 94of locking wire 90 projects beyond the peripheral side edge of slide16″. In the closed position, end 94 of locking wire 90 extends into acomplementary locking recess 96 formed in guide 42 so that end 94operates as a detent to arrest or otherwise prevent movement of theligating slide 16′. The engagement between end 94 and locking recess 96provides a positive stop for the ligating slide 16″ in the openposition.

[0052] Extending through the thickness of the ligating slide 16″ is anaperture or opening 98 within which a length of the locking wire 90 islocated. To release the ligating slide 16″ from the closed position, thelocking wire 90 is bent or deflected using a suitable tool (not shown)occlusal/gingivally toward an inner edge 100 surrounding and definingthe opening 98 so that end 94 of the locking wire 90 is withdrawn fromthe locking recess 96, as shown in FIG. 9. The ligating slide 16″ isthen freely movable using a occlusal/gingivally force applied by tool102 from the closed position to the open position for inserting archwire143 into the archwire slot 38. The locking wire 90 is formed from anymaterial of sufficient bendability to permit repeated movements ordeflections for withdrawing end 94 from the locking recess 96. Morespecifically, the material forming the locking wire 90 should undergoelastic deformation without significant plastic deformation when bent ordeflected to withdraw end 94 from the locking recess 96. As a result,the locking wire 90 is capable of extending to engage the end 94 inlocking recess 96 when the ligating slide 16″ is moved from the openposition to the closed position after the archwire 43 has been insertedin the archwire slot 38. The locking wire 90 may be constructed from,for example, a superelastic Ni/Ti alloy. It is contemplated that thelocking wire 90 may be bent at about a 90° angle into an L-shape andattached to the ligating slide 16″ with the bend visible in opening 98such that a force applied to the locking wire 90 in a mesial/distaldirection withdraws end 94 from locking recess 96.

[0053]FIG. 10 illustrates an alternative method of deflecting thelocking wire 90 in order to remove end 94 from the locking recess 96 torelease the ligating slide 16″ so that slide 16″ can be moved from itsclosed position to its open position. Specifically, the portion of thelocking wire 90 visible in opening 98 is pushed inwardly (in a lingualdirection) with one end 106 of a suitable tool having a collar 104 of alarger diameter than an inner diameter of opening 98 to limit the inwarddisplacement of locking wire 90.

[0054] With reference to FIGS. 11-14 and in accordance with analternative embodiment of the invention, an orthodontic bracket,generally indicated by reference numeral 110, for use in correctiveorthodontic treatments includes a bracket body 112, a self-ligationinsert 114 mounted in the bracket body 112, a movable ligating slide 116slidably coupled with the self-ligation insert 114, and a resilientengagement member or spring arm 118. The bracket body 112, self-ligationinsert 114, ligating slide 116 and spring arm 118 are formed frommaterials identical to the materials described above for correspondingcomponents of orthodontic bracket 10 (FIGS. 1-5).

[0055] The bracket body 112 includes a bonding base 120 and a recessedslot or groove 122, best visible in FIG. 11, extending generally in amesial/distal direction. The bonding base 120 is configured to besecured to the enamel of a tooth 124 in any conventional manner, forexample, by an appropriate orthodontic cement or adhesive. Morespecifically, the bracket body 112 is typically secured to tooth 124with an orientation such that gravity assists the movement of ligatingslide 116 from a closed position (FIG. 13) defining a latched conditionor to an open position (FIG. 12) defining an unlatched condition andhelps to maintain the ligating slide 116 in the open position until amoving force is applied. When tooth 124 is carried by the patient'slower jaw, the bracket body 112 is bonded to the mandibular tooth 124such that the ligating slide 116 moves in a gingival to occlusaldirection when closing and, hence, slide 116 moves generally in thedirection of gravity. When tooth 124 is carried by the patient's upperjaw, the bracket body 112 is bonded to the maxillary tooth 124 such thatthe ligating slide 116 moves in a occlusal to gingival direction whenclosing and slide 116 still moves generally in the direction of gravity.

[0056] Two orthodontic tie wings 126, 128 may be optionally provided onthe bracket body 112 with a spaced relationship in a mesial/distaldirection. Tie wings 126, 128 provide orthodontic attachment points to,for example, apply torsional forces to the tooth 124.

[0057] With continued reference to FIGS. 11-14, the self-ligation insert114 includes a base wall 136 and a pair of opposed slot or side walls130, 132 projecting outwardly in a labial or buccal direction from thebase 136. The side walls 130, 132 and base wall 136 are embedded withinthe material of the bracket body 112 and generally coextensive with thegroove 122 in the bracket body 112. The side walls 130, 132 and basewall 136 collectively define an archwire slot 138 extending generally ina mesial/distal direction. The archwire slot 138 is designed to receivean orthodontic archwire 143 (FIG. 14) in the same manner as conventionalorthodontic brackets. Portions of the bracket body 112 overlie side wall130 of self-ligation insert 114 to make the insert 114 resistant to apullout force directed outwardly relative to tooth 124.

[0058] Side wall 130 has a wedge-shape, as most evident in FIG. 14, thatoperates to increase the pullout resistance of insert 114. Theconfiguration of side wall 130 at the interface with the bracket body112 creates a draft or reverse angle that tend to lock the insert 114with bracket body 112. In particular, the draft increases the resistanceof insert 114 to a pullout force directed outwardly from tooth 124.

[0059] The self-ligation insert 114 further includes a substantiallyplanar member 134 extending from side wall 132 and a pair of guides 140,142 carried by planar member 134. The guides 140, 142 are located with aspaced relationship in the mesial/distal direction. The guides 140, 142project outwardly from the planar member 134 in a labial or buccaldirection and are positioned on the side of the archwire slot 138. Guide140 includes a lip 140 a projecting in a mesial/distal direction that isoriented toward a lip 142 a on guide 142 also projecting in amesial/distal direction. Because the insert 114 includes guides 140, 142formed from metal, the insert 114 has a strength sufficient to constructan orthodontic bracket 110 that is self-ligating.

[0060] With continued reference to FIGS. 11-14, the ligating slide 116is a generally planar structure having a central portion 144, anelongated groove or recess 146 (FIG. 14) in the central portion thatopens toward the tooth 124, a flange 148 extending outwardly in amesial/distal direction from a side edge of central portion 144, and aflange 150 extending outwardly in a mesial/distal direction from anopposite side edge of central portion 144. Flanges 148 and 150 each arejoined to the central portion 144 by a smoothly-curved junction. Flange148 moves occlusal/gingivally in the C-shaped space between lip 140 a ofguide 140 of the self-ligating insert 114 and planar member 134.Similarly, flange 150 moves occlusal/gingivally in the C-shaped spacebetween the lip 140 b of guide 142 and planar member 134.

[0061] Elongated recess 146 extends between an open end 154 and a closedend 156 opposite the open end 154. A throughhole or aperture 152 isformed near the open end 154. A labial side of the central portion 144of the ligating slide 116 includes a channel 158 that tapers or narrowsin a direction from a leading edge 160 of slide 116 toward a trailingedge 162 of slide 116. Aperture 152 is located near, and usually at, theapex of the channel 158, which converges toward aperture 152. Channel158 is on a surface of the central portion 144 opposite to the surfacebearing elongate recess 146. Channel 158 may be oriented and configuredin any manner sufficient to guide tip 184 (FIG. 15) toward aperture 152,as described below. For example, channel 158 may lack tapering oraperture 152 may have a location other than near the apex of channel158.

[0062] With continued reference to FIGS. 11-14, the ligating slide 116is movable occlusal/gingivally relative to the bracket body 112 betweenopen and closed positions. In the open position, the archwire slot 138is accessible for inserting an arch wire 143 (FIG. 14) is insertableinto the archwire slot 138 and the closed position in which the archwire 143 is captured or enclosed in the archwire slot 138. When theligating slide 116 is in the closed position, the leading edge 160 ofthe slide 116 is located adjacent to, and underlies, a smoothly-curvingdeflecting element 166 disposed on bracket body 112 generally betweenthe tie wings 126, 128. Deflecting element 166 operates during chewingto cover and shield the leading edge 160 of the slide 116 from thechewed material in the patient's oral cavity. As a result, the chewedmaterial cannot contact the leading edge 160, which increases theresistance of slide 116 to movement during chewing. The inventioncontemplates deflecting element 166 may be a continuous ridge, asdepicted in FIGS. 11-14, or may have other constructions adequate toshield leading edge 160, such as an aligned row of discontinuous andspaced-apart projections. In any event, the smooth convex curvature ofthe deflecting element 166 deflects chewed material or other objects ina direction away from leading edge 160.

[0063] When the ligating slide 116 is in the open position, portions ofthe trailing edge 162 of the slide 116 abut against stops 168, 170formed on guides 140, 142, respectively, each having the form of asubstantially flat surface. Stops 168, 170 prevent accidental orunintentional detachment of the ligating slide 112 from theself-ligation insert 114 during use when the ligating slide 112 ispositioned in the open position. The stops 168 and 170 collectivelylimit the occlusal/gingival range of movement of the ligating slide 116.

[0064] With continued reference to FIGS. 11-14, the spring arm 118regulates the movement of the ligating slide 116 relative to the bracketbody 112 and self-ligating insert 114 is confined or trapped between theself-ligating insert 114 and the ligating slide 116. The spring arm 118is generally L-shaped and is aligned generally perpendicularly relativeto the archwire slot 138. An inwardly-extending prong 172 of the springarm 118 is received in a recess 174 formed in the self-ligating insert114. The free end of the spring arm 118 is provided with anoutwardly-extending detent or projection 176, which correspondsgenerally in cross-sectional profile with the cross-sectional profile ofthe aperture 152 and, to that end, may be rectangular or oval-shaped incross-section. The projection 176 extends into aperture 152 in theligating slide 116 when slide 116 is located in the closed position. Theengagement between the projection 176 and the aperture 152 holds theligating slide 116 in the closed position against movement that wouldotherwise open the slide, assisted by deflecting element 166 that whichshields the leading edge 160 of ligating slide 116 from contact withchewed material. As a result, ligating slide 116 is unlikely to beunintentionally moved from the closed position to the open position.

[0065] The free end of spring arm 118 carrying projection 176 iselastically compressed when captured within the elongated recess 146.Specifically, the free end of spring arm 118 is capable of resilientlyflexing or deforming outwardly toward the ligating slide 116, when theprojection 176 is aligned with aperture 152, for selectively engagingthe projection 176 with the aperture 152 so as to lock the ligatingslide 116 in its closed position. To that end, the spring arm 118 isresiliently biased in a direction that forces the projection 176outwardly away from the tooth and toward the ligating slide 116.

[0066] The ligating slide 116 includes a pair of projections or stops178, 180 in the form of substantially flat surfaces that are oriented toface the stops 168, 170, respectively, on the insert 114. When theligating slide is fully open, stops 178, 180 each contact and abutagainst a corresponding one of the stops 168, 170 to provide a positivemovement obstruction. The projection 176 of spring arm 118 contacts theelongated recess 146 in the open position with a force sufficient tomaintain the ligating slide 116 in the open position in opposition to alesser force applied occlusal/gingivally.

[0067] The ligating slide 116 is moveable between the open and closedpositions without overcoming a significant biasing force during thetransition between open and closed positions. In other words, the springarm 118 locks the ligating slide 116 in the open and closed positionssubstantially independent of the biasing force of the spring arm 118. Inpositions between open and closed, the ligating slide 116 is freelymovable by a force significantly less than the force required to movespring-biased slides of conventional self-ligating brackets. Theligating slide 116 is captivated with the insert 114 regardless ofwhether slide 116 is in the open or closed position.

[0068] With reference to FIG. 15, a spring release tool 182 includes atip 184, an annular collar or shoulder 186 surrounding the tip 184, anda handle 188 for gripping and manipulating the tool 182. The tip 184 isinserted into the aperture 152 in the ligating slide 116 and, whenpressed inward, forces the projection 176 inwardly to disengage theprojection 176 from the aperture 152 and allow the ligating slide 116 tobe moved from the closed position to the open position. As visibilityinside the mouth is limited and the aperture 152 is a relatively smallfeature, the channel 158 operates to guide the tip 184 toward theaperture 152. Aperture 152 includes a curved portion 152 a that aids incentering the tip 184 in aperture 152. The handle 188 tapers toward acurved bend 190 that orients the tip 184 for accessing brackets 110mounted to distal teeth 124. Bend 190 may be reduced in angle or omittedfrom spring release tool 182 for accessing mesial teeth 124 that aremore accessible.

[0069] The shoulder 186 operates to limit the depth of insertion of tip184 into the aperture 152 by contacting portions of the ligating slide116 surrounding aperture 152. Specifically, the projection of tip 184beyond shoulder 186 is limited such that a damaging force cannot beapplied to the spring arm 118. Generally, the insertion depth is greaterthan or equal to the thickness of the slide surrounding aperture 152 butless than a distance that would apply a damaging force. In oneembodiment, the tip 184 projects from shoulder 186 by a distancesubstantially equal to the thickness of the slide 166 surrounding theaperture 152. In one specific embodiment, tip 184 projects 0.01″ fromthe shoulder 186 so that the maximum penetration distance of tip 184into the aperture 152 is 0.01″. If spring arm 118 is deflected by adistance substantially greater than required to disengage projection 176from aperture 152, the spring arm 118 may be stressed beyond the elasticlimit of the material and thereby damaged.

[0070] The invention contemplates that a channel similar to channel 158may be used for other purposes on an orthodontic bracket, similar toorthodontic bracket 110, or other dental appliance to guide the tip of atool to a defined destination on a ligating slide 116 or otherstructure. Therefore, this aspect of the invention is not limited todirecting a tool tip 184 to aperture 152 and depressing a projection 176from an aperture 152. In certain embodiments of the invention, theaperture 152 may be used to apply an inward force with tool tip 184 todisengage the projection 176 from a recess (not shown) formed in theligating slide 116 that is separate and distinct from aperture 152.

[0071] In use and with reference to FIGS. 11-15, the ligating slide 116in the closed position blocks access to the archwire slot 138 tocaptivate the archwire 143 therein. The ligating slide 116 is unlockedby placing the tip 184 of the spring release tool 182 generally in thechannel 158 and moving tip 184 toward the aperture 152. The tapering ofthe channel 158 guides the tip 184 into the aperture 152. When the tip184 is positioned within aperture 152, an inward force is applied by thetip 184 to projection 176 sufficient to overcome the bias applied byspring arm 118 and to disengage the projection 176 from the aperture152. The ligating slide 116 is movable using a force applied by the tip182 occlusal/gingivally toward the open position in a slidably mannerguided by cooperation between the flanges 148, 150 and guides 140, 142.The motion of the ligating slide 116 is positively stopped in the openposition by contact between the stops 178, 180 on ligating slide 116 andstops 168, 170 on the insert 114.

[0072] The ligating slide 116 is freely movable occlusal/gingivally fromthe open position to the closed position without overcoming the springforce applied by the spring arm 118. To place the ligating slide 116 inthe closed position, slide 116 is moved occlusal/gingivally using tool182 or the clinician's finger until the projection 176 springs outwardlyunder the bias applied by spring arm 118 into aperture 152. The ligatingslide 116 is then securely locked in the closed position. The engagementof the projection 176 into the aperture 152 may create a tactile effectwhich is perceptible to a clinician and/or emits an audible sound, suchas a click, that is likewise perceptible by a clinician. The resilientbias applied by the spring arm 118 does not act on the ligating slide116 other than to engage the projection 176 with the aperture 152. Itfollows that the spring arm 118 is not operatively coupled with theligating slide 116 for providing a force that moves the ligating slide116 relative to the bracket body 112. Moreover, the ligating slide 116does not have to overcome the resilient force of the spring arm 118during movement.

[0073] While the invention has been illustrated by a description ofvarious embodiments and while these embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The invention in its broader aspects istherefore not limited to the specific details, representative apparatusand methods, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thespirit or scope of applicants' general inventive concept.

Having described the invention, what is claimed is:
 1. A self-ligatingorthodontic bracket for coupling an archwire with a tooth, comprising: abracket body configured to be mounted to a tooth, said bracket bodyincluding an archwire slot; a ligating slide carried by said bracketbody for movement between an open position in which an archwire isinsertable into said archwire slot and a closed position in which saidligating slide retains the archwire in said archwire slot, said ligatingslide including a recess; and a resilient engagement member positionedto engage said recess when said ligating slide is in said closedposition for constraining movement of said ligating slide relative tosaid bracket body.
 2. The self-ligating orthodontic bracket of claim 1wherein said ligating slide includes a groove with a closed end, saidresilient engagement member moving within said groove as said ligatingslide is moved between said open and closed positions such that saidresilient engagement member engages said closed end when said ligatingslide is in said open position.
 3. The self-ligating orthodontic bracketof claim 1 wherein said resilient engagement member comprises a springarm coupled with said bracket body and having a free end carrying adetent.
 4. The self-ligating orthodontic bracket of claim 1 wherein saidresilient engagement member comprises a pin configured to be receivedwithin said aperture in said ligating slide and a coil spring biasingsaid pin toward said ligating slide.
 5. The self-ligating orthodonticbracket of claim 1 wherein said resilient engagement member providespositive stops for said ligating slide in said open and closed positionswithout overcoming a biasing force of said resilient engagement memberduring transitions between said open and closed positions.
 6. Theself-ligating orthodontic bracket of claim 1 wherein said resilientengagement member locks said ligating slide in said open and closedpositions independent of a biasing force of said resilient engagementmember.
 7. The self-ligating orthodontic bracket of claim 1 wherein saidrecess is a throughhole extending through said ligating slide and saidspring arm includes a detent that engages said throughhole when saidligating slide is in said open position.
 8. A self-ligating orthodonticbracket for coupling an archwire with a tooth, comprising: a ligatingslide; a bracket body configured to be mounted to a tooth, said bracketbody including an archwire slot and a pair of opposed guides supportingsaid ligating slide, said pair of opposed guides guiding said ligatingslide for movement between an open position in which an archwire isinsertable into said archwire slot and a closed position in which thearchwire is retained in said archwire slot, at least one of said pair ofopposed guides including a recess; and a resilient engagement memberpositioned to engage said recess when said ligating slide is in saidclosed position for constraining movement of said ligating sliderelative to said bracket body.
 9. The self-ligating orthodontic bracketof claim 8 wherein said resilient engagement member comprises a bendablewire having a first end engaging said recess in said closed position anda second end affixed to said ligating slide, said bendable wire beingmovable by a force sufficient to remove said first end from said recessin order to release said ligating slide for movement from said closedposition to said open position.
 10. The self-ligating orthodonticbracket of claim 9 wherein said ligating slide includes a throughholepositioned for accessing said bendable wire to cause movement.
 11. Theself-ligating orthodontic bracket of claim 9 wherein first end of saidbendable wire is capable of reengaging said recess when said force isremoved.
 12. An apparatus for coupling an archwire with a tooth,comprising: a bracket body configured to be mounted to a tooth, saidbracket body including an archwire slot; a ligating slide carried bysaid bracket body for movement between an open position in which anarchwire is insertable into said archwire slot and a closed position inwhich said ligating slide retains the archwire in said archwire slot,said ligating slide including a rear surface facing the tooth, a frontsurface opposite to said rear surface, and an aperture extending fromsaid front surface to said rear surface; a resilient engagement membercapable of engaging said ligating slide in said closed position forconstraining movement of said ligating slide relative to said bracketbody; and a tool including a shoulder and a tip projecting from saidshoulder by a distance sufficient to deflect said resilient engagementmember so that said ligating slide may be moved from said closedposition to said open position when said shoulder contacts a portion ofsaid ligating slide surrounding said aperture.
 13. The apparatus ofclaim 12 wherein said distance is greater than or equal to a thicknessof said ligating slide between said front surface and said rear surface.14. The apparatus of claim 13 wherein said distance is insufficient toapply a stress exceeding the elastic limit of the resilient engagementmember.
 15. The apparatus of claim 12 wherein said resilient engagementmember protrudes into said aperture for constraining movement of saidligating slide relative to said bracket body.
 16. A self-ligatingorthodontic bracket for coupling an archwire with a tooth in conjunctionwith a tool, comprising: a bracket body configured to be mounted to atooth, said bracket body including an archwire slot; and a ligatingslide carried by said bracket body for movement between an open positionin which an archwire is insertable into said archwire slot and a closedposition in which said ligating slide retains the archwire in saidarchwire slot, said ligating slide including a rear surface facing thetooth, a front surface opposite to said rear surface, and atool-engaging element accessible from said front surface, said frontsurface including a channel effective for guiding the movement of a toolcontacting said front surface and moving toward said tool engagingelement.
 17. The self-ligating orthodontic bracket of claim 16 whereinsaid exposed channel is tapered.
 18. The self-ligating orthodonticbracket of claim 17 wherein said exposed channel converges toward saidaperture.
 19. The self-ligating orthodontic bracket of claim 16 whereinsaid tool-engaging element is an throughhole extending from said frontsurface to said rear surface.
 20. The self-ligating orthodontic bracketof claim 19 further comprising: a resilient engagement member positionedto engage said aperture when said ligating slide is in said closedposition for constraining movement of said ligating slide relative tosaid bracket body, said resilient engagement member capable of beingremoved from said aperture by a force applied by the spring release toolso that said ligating slide may be moved from said closed position tosaid open position.
 21. A self-ligating orthodontic bracket for couplingan archwire with a tooth, comprising: a bracket body configured to bemounted to a tooth, said bracket body including an archwire slot; aligating slide carried by said bracket body for movement between an openposition in which an archwire is insertable into said archwire slot anda closed position in which said ligating slide retains the archwire insaid archwire slot, said ligating slide including a peripheral edge; anda deflecting element on said bracket body that deflects objects in apatient's oral cavity away from said peripheral edge when said ligatingslide is in said closed position and said bracket body is mounted to thetooth.
 23. The self-ligating orthodontic bracket of claim 22 whereinsaid peripheral edge has a length, and said deflecting element comprisesa continuous ridge overlying said peripheral edge along said length. 24.The self-ligating orthodontic bracket of claim 22 wherein saiddeflecting element is a smoothly-curving ridge.
 25. A self-ligatingorthodontic bracket for coupling an archwire with a tooth, comprising: abracket body configured to be mounted to a tooth, said bracket bodyincluding an archwire slot and a first stop element; a ligating slidecarried by said bracket body for movement between an open position inwhich an archwire is insertable into said archwire slot and a closedposition in which said ligating slide retains the archwire in saidarchwire slot, said ligating slide including at least one second stopelement that abuts said first stop element when said ligating slide isin said open position.
 26. The self-ligating orthodontic bracket ofclaim 25 wherein said bracket body includes a guide that captivates saidligating slide for sliding movement relative to said bracket body, saidsecond stop element positioned on said guide.
 27. The self-ligatingorthodontic bracket of claim 25 wherein said ligating slide includes anaperture, and further comprising: a resilient engagement memberincluding a detent positioned to engage said aperture when said ligatingslide is in said closed position for constraining movement of saidligating slide relative to said bracket body.
 28. The self-ligatingorthodontic bracket of claim 25 wherein said resilient engagement membercontacts said ligating slide in at least said open position with a forcesufficient to maintain said ligating slide in said open position.
 29. Aself-ligating orthodontic bracket for coupling an archwire with a tooth,comprising: a metallic self-ligating assembly including an archwire slotand a ligating member movable between an open position in which anarchwire is insertable into said archwire slot and a closed position inwhich the archwire is retained in said archwire slot; and a bracket bodyconfigured to be mounted to a tooth and carrying said metallicself-ligating assembly, said bracket body comprising a non-metallicmaterial.
 30. The self-ligating orthodontic bracket of claim 29 whereinsaid non-metallic material is a polymer, a filled polymer composite, ora ceramic.
 31. The self-ligating orthodontic bracket of claim 29 whereinsaid non-metallic material is sapphire, polycrystalline aluminum oxide,toughened zirconia, or yttrium-stabilized zirconia.
 32. Theself-ligating orthodontic bracket of claim 29 wherein said non-metallicmaterial is polycarbonate, an acrylic-based thermoplastic resin, or anacrylic thermoset resin.
 33. The self-ligating orthodontic bracket ofclaim 29 wherein at least one of said walls of said self-ligating insertis wedge-shaped for increasing pull-out resistance in directiongenerally perpendicular to the tooth.
 34. The self-ligating orthodonticbracket of claim 29 further comprising a metallic engagement membercapable of constraining movement of said ligating member relative tosaid bracket body when said ligating member is in the closed position.35. The self-ligating orthodontic bracket of claim 29 wherein saidself-ligating assembly further includes at least one guide and saidligating member is slidably movable within said at least one guide.